The patent document of EP 1 539 523 B1 discusses how the automatic emergency braking process is not triggered until after a warning time period has expired, during which time period the driver is provided with the possibility of avoiding the automatic emergency braking process by intervening in the form of a driver's braking request. The warning time period is divided here chronologically into two stages, wherein according to a first warning stage time period a visual and/or acoustic warning to the driver is issued. If the driver does not react thereto, within the scope of a second warning stage time period a partial braking operation is initiated with a partial braking deceleration which is less than a predefined (maximum) emergency braking deceleration. The emergency braking process is triggered automatically only if the driver also allows the second warning stage time period to pass without activating the brake. Within the scope of the warning time period, the driver therefore has the possibility of averting the hazard situation by activating the brake.
In this context, the warning time period is permanently predefined or is set as a function of the vehicle mass, the coefficient of friction of the lining of the wheel brake apparatuses of the vehicle, the condition of the underlying surface or the visibility conditions.